With the development of the electric power industry and the increasing city underground cable system, the requirement for the power cable is increasing rapidly, specially, for the power cable of medium voltage in the range of 6-35 kV. At the same time, the requirement for the power cable accessories associated with the power cable of medium voltage is also increasing more rapidly.
The removable T-shaped cable connector (hereinafter simply referred as T-shaped connector), as one kind of the power cable accessory, is used. The T-shaped connector sheath generally comprises: a T-shaped main insulation bushing layer; an inner semi-conductive shielded layer which is disposed in the T-shaped main insulation bushing layer and integrally formed with it; and an outer semi-conductive shielded layer which is disposed on an outer surface of the T-shaped main insulation bushing layer and integrally formed with it. In order to control electric field distribution of the cable shield opening, an adapter in which an electric stress control layer is imbedded must be connected during usage of the cable connector. The adapter and the T-shaped connector sheath together constitute the electric stress control layer and the main insulation assembly. The manufacturing process of the adapter imbedded with the stress control layer is very complicated. Further, since the prior adapter imbedded with the stress control layer must be preformed, one type of adapter only can be used to the cable with a corresponding cable cross section. Thus, the prior adapter can not be easily interchanged.
In the EP patent No. 691721(B1), another T-shaped cable connector of this type is disclosed. The adapter of the EP patent has an imbedded stress control layer which is preformed. Thus, one type of adapter only can be used to the cable with a corresponding cable cross section. In the CN patent No. 2627669Y, a T-shaped cable connector and an adapter that can be drawn out by a core ribbon are disclosed. The adapter of the patent has an imbedded stress control layer. Since a “cold-shrink” mounting manner (that is, in the manner, after drawing out a core ribbon during mounting process, the rubber will automatically shrink to the original state) is adopted, the patent solved above problem that it is very difficult to mount the adapter. However, it is still needed to imbed a stress control layer into the adapter.
In the U.S. Pat. No. 6,991,484, a cold-shrink integral T-shaped cable connector is disclosed. The T-shaped cable connector of the patent is not provided with the adapter imbedded with a stress control layer. The integral T-shaped cable connector is mounted in a cold-shrink manner, which also solve above problem. However, the thickness of the crimp type terminal matching with the cold-shrink integral T-shaped cable connector is increasing as the cable cross section is increasing. Once the cable cross section exceeds a certain range, the T-shaped connector cable connecting chamber will not come into contact with the cable insulator and the cable outer shield since the thickness of the crimp type terminal increases, which will cause insufficient insulating strength for the cable. In sum, although above patents have solves the difficulty in connection with the mounting operation, they still have other defects that have not been solved.